Communication apparatus and method of determining route

ABSTRACT

A communication apparatus stores topology information that is shared by communication apparatuses included in a network and representing connection states between the communication apparatuses. The topology information includes port identification information for identifying ports that are connectable to each other within each communication apparatus. The communication apparatus determines a route by sequentially selecting a port that can be connected to a port, to which transmission data is input based on the port identification information.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of theprior Japanese Patent Application No. 2011-086788, filed on Apr. 8,2011, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments discussed herein are directed to a communicationapparatus and a method of determining a route.

BACKGROUND

Conventionally, there is multi-protocol label switching (MPLS) thatenables the operation of a network based on end-to-end paths a networkincluding a plurality of nodes by introducing the concept of a labelswitch to an internet protocol (IP) network. In addition, not only forthe IP network, as a technique for operating a network based on variouskinds of paths in an autonomous and distributed manner, generalizedmulti-protocol label switching (GMPLS) is used. The GMPLS operates atime division multiplexing (TDM) network such as a synchronous digitalhierarchy (SDH)/synchronous optical network (SONET) in an autonomous anddistributed manner. In addition, as another example, the GMPLS operatesa wavelength switching network or an optical transport network (OTN) inan autonomous and distributed manner.

In the MPLS or the GMPLS, as a technique for signaling through anend-to-end path, a resource reservation protocol-traffic engineering(RSVP-TE) is used. Specifically, in the MPLS or the GMPLS, a route froma start node to an end node is calculated by using topology informationof a network that is collected by open shortest path first extended fortraffic engineering (OSPF-TE). Then, in the MPLS or the GMPLS, theRSVP-TE is autonomously transmitted and received between nodes.Accordingly, in the MPLS or the GMPLS, the communication of a mainsignal is started by stretching a label switched pass (LSP) on theend-to end. Such a technique has been discussed in the internetengineering task force (IETF), the optical internetworking forum (OIF),the international telecommunication union (ITU), and the like, and astandardization operation thereof is in progress. (see, for example,International Publication Pamphlet No. WO 2004/102903, JapaneseLaid-open Patent Publication No. 2008-60755, Japanese Laid-open PatentPublication No. 2008-85642, and International Publication Pamphlet No.WO 2005/101759.)

However, according to a conventional technique, in a network thatincludes a plurality of nodes, there is a problem in that an erroroccurs in the selection of a route relating to data transmission.Specifically, according to the conventional technique, in a case wherethere is a restriction on the connection destination of a route relatingto data transmission, it is difficult to calculate a route to which therestriction is applied, and accordingly, an error occurs in theselection of a route relating to the data transmission.

FIG. 25A is an explanatory diagram illustrating a conventional problemoccurring in a case where there is a restriction on the connectiondestination. In FIG. 25A, each node of Node A to Node D, for example,includes ports #1 to #8, and, in a network including the nodes, a costvalue is assigned to each route connecting the ports between nodes. Thecost value represents a data transmission state in a route up to a nodeas a link destination and, for example, is a value corresponding to aparameter such as a band, a speed, a distance, or a time relating tocommunication. FIG. 25A illustrates that a smaller cost value representsa route that is more optimal than other routes. For the calculation of aroute, for example, a Dijkstra algorithm, a Bellman-Ford algorithm, orthe like may be used, which acquires a shortest route as a constrainedshortest path first (CSPF). In the calculation of a route using such analgorithm, a route having the minimum sum of assigned cost values iscalculated. Here, it is assumed that all the bands are in a vacant statein each port, and each node maintains topology information that isadvertised by the OSPF-TE. Here, the number of ports may be differentfrom node to node.

In FIG. 25A, in Node A and Node D, routes each having a restriction onthe connection are denoted by broken lines. Specifically, there arerestrictions on the connection destinations between ports #3-1 to #3-4and port #4 of Node A, and between port #4 and ports #3-1 to #3-4 ofNode D. In the description of FIG. 25A, for example, a case will bedescribed in which a start point is port “#1” of Node A and an end pointis port “#1” of Node D in a network including a plurality of nodes fromNode A to Node D. In addition, it is assumed that the calculation of aroute is performed by Node A.

In the above-described configuration, Node A calculates a route in whichthe sum of assigned cost values is the minimum. As the route selected asabove, a route is selected in the order of “port “#1” and “#2” of NodeA”, “ports “#1” and “#4” of Node B”, and “port “#4” of Node D”. As aresult, in the network illustrated in FIG. 25A, a route denoted by adotted line is selected. Here, in Node D, connection destinations thatcan be connected to port #4 are ports #3-1 to #3-4. Thus, according to aconventional technique, in the network illustrated in FIG. 25A, it isdifficult to select a route reaching port #1 of Node D as the end point,so that an error occurs. In addition, the route that is to be originallyselected is a route, which is denoted by a solid line illustrated inFIG. 25A, passing through port #3 of Node B.

Accordingly, a supervisor is aware of the presence of a node having arestriction on the connection destination within the network and setsinformation that selects a route passing through a specific port. FIG.25B is a diagram illustrating an example in which information used forselecting a route passing through a specific port. In the exampleillustrated in FIG. 25B, a supervisor, for example, sets informationused for selecting a route passing through port #2 of Node A and port #2of Node D. For example, the information used for selecting a routepassing through a specific port may be referred to as “Includedesignation”. In FIG. 25B, ports that are designated for “Includedesignation” are denoted by black circles. Node A, as illustrated inFIG. 25B, selects a route that includes “ports “#1” and “#3” of Node B”based on “Include designation”.

However, originally, one of the advantages of the MPLS or the GMPLS isto autonomously calculate a route without involving a supervisortherein. However, when a system is configured such that thesupervisor-has to set “Include designation” and additional maintenancestep will be added to a conventional one for considering the setting of“Include designation” to a specific port of a specific node. Inaddition, “Include designation” may be set when a restriction is newlyset in a network in which there has been originally no restriction. Whena restriction is newly set, a maintenance sequence for performingsetting not using the GMPLS is required, compared to a conventionalcase.

SUMMARY

According to an aspect of an embodiment of the invention, acommunication apparatus includes a memory that stores topologyinformation shared by nodes included in a network and representingconnection states between the nodes, the topology information includingport identification information used for identifying ports that areconnectable to each other within each node; and a processor thatdetermines a route by sequentially selecting a port that can beconnected to a port, to which transmission data is input, within eachnode, based on the port identification information stored in the memory.

The object and advantages of the embodiment will be realized andattained by means of the elements and combinations particularly pointedout in the claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and arenot restrictive of the embodiment, as claimed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of the hardwareconfiguration of a communication apparatus that passes through a switch;

FIG. 2 is a diagram illustrating an example of the hardwareconfiguration of a communication apparatus that does not pass through aswitch;

FIG. 3 is a diagram illustrating an example of the functional blocks ofa communication apparatus according to a first embodiment;

FIG. 4A is a diagram illustrating an example of the configuration of arestriction information Sub-TLV;

FIG. 4B is a diagram illustrating an example of the configuration of arestriction information Sub-TLV;

FIG. 5 is a diagram illustrating a configuration example of an OpaqueLSA;

FIG. 6 is a diagram illustrating an overview of a Sub-TLV;

FIG. 7A is a diagram illustrating a configuration example of atransponder card;

FIG. 7B is a diagram illustrating an example of restriction informationthat is set in accordance with the transponder card illustrated in FIG.7A;

FIG. 8A is a diagram illustrating a configuration example of a muxpondercard;

FIG. 8B is a diagram illustrating an example of restriction informationthat is set in accordance with the muxponder card illustrated in FIG.8A;

FIG. 9A is a diagram illustrating a configuration example of a muxpondercard in which a SW, in which a connection destination is restricted, isbuilt;

FIG. 9B is a diagram illustrating an example of the restrictioninformation that is set in accordance with the muxponder cardillustrated in FIG. 9A;

FIG. 10A is a diagram illustrating a configuration example of an IF cardin which a SW is built;

FIG. 10B is a diagram illustrating an example of restriction informationthat is set in accordance with the IF card illustrated in FIG. 10A;

FIG. 11A is a diagram illustrating a configuration example of an IF cardthat passes through a SW card;

FIG. 11B is a diagram illustrating an example of restriction informationthat is set in accordance with the IF card illustrated in FIG. 11A;

FIG. 12A is a diagram illustrating a configuration example of an IFcard, which has a restriction, passing through a SW card;

FIG. 12B is a diagram illustrating an example of restriction informationthat is set in accordance with the IF card illustrated in FIG. 12A;

FIG. 13A is a diagram illustrating a configuration example of an IF cardin a case where the IF card having the SW illustrated in FIG. 11A builttherein is removed;

FIG. 13B is a diagram illustrating an example of restriction informationthat is set in accordance with the IF card illustrated in FIG. 13A;

FIG. 14 is a diagram illustrating an example of route calculation in acase where the start and end ports have F Bits of “1”;

FIG. 15 is a diagram illustrating an example of route calculation in acase where ports of which the F Bits are “1” are continuous;

FIG. 16 is a diagram illustrating an example of route calculation in acase where a muxponder card is an end point;

FIG. 17 is a diagram illustrating an example of route calculation in acase where an F Bit is not used;

FIG. 18 is a diagram illustrating an example of route calculation in acase where an F Bit is not used;

FIG. 19 is a flowchart illustrating an example of the flow of a topologyinformation setting process at the time of setting the IF card accordingto the first embodiment;

FIG. 20 is a flowchart illustrating an example of the flow of a topologyinformation setting process at the time of removing an IF card accordingto the first embodiment;

FIG. 21 is a flowchart illustrating an example of the flow of a topologyinformation setting process at the time of changing an IF card accordingto the first embodiment;

FIG. 22 is a flowchart illustrating an example of the flow of a topologyinformation setting process at the time of changing a restrictionaccording to the first embodiment;

FIG. 23 is a flowchart illustrating an example of the flow of a processof reflecting the restriction item according to the first embodiment onthe route calculation;

FIG. 24 is a flowchart illustrating an example of the flow of a routecalculating process according to the first embodiment;

FIG. 25A is a diagram illustrating a conventional problem in a casewhere there is a restriction of a connection destination; and

FIG. 25B is a diagram illustrating an example of setting informationused for selecting a route passing through a specific port.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present invention will be explained withreference to accompanying drawings.

In addition, the invention is not limited to embodiments describedhereinafter.

[a] First Embodiment

Hardware Configuration of Communication Apparatus

Hereinafter, the hardware configuration of a communication apparatusaccording to a first embodiment will be described with reference toFIGS. 1 and 2. FIG. 1 is a diagram illustrating an example of thehardware configuration of the communication apparatus that passesthrough a switch. FIG. 2 is a diagram illustrating an example of thehardware configuration of the communication apparatus that does not passthrough a switch.

For example, as illustrated in FIG. 1, the communication apparatusincludes a maintenance managing unit and a main signal processing unit.Out of these units, the maintenance managing unit, for example, includesa central processing unit (CPU), a random access memory (RAM), and anon-volatile memory such as a flash memory or a compact flash (CF). Inaddition, the maintenance managing unit performs overall control of theCPU, the RAM, and the non-volatile memory and performs monitoring,various settings, and the like of the entire apparatus through a controlbus.

Meanwhile, the main signal processing unit, for example, includes aninterface (IF) card and a switch. For example, the switch is a switch(SW) card that has a cross-connecting function. The IF card, forexample, includes a small form factor pluggable (SFP)/10 gigabit smallform factor pluggable (XFP) and an IF control circuit. The SFP/XFP, forexample, is in compliance with various main signal specifications andinputs and outputs various main signals. The IF control circuit, forexample, performs a process according to each frame format. In otherwords, the main signal processing unit performs control relating tosynchronous optical network (SONET)/a synchronous digital hierarchy(SDH) in the case of a SONET/SDH signal and performs control relating toan optical transport network (OTN) in the case of an OTN signal. TheSFP/XFP and the IF control circuit may be included in one card, and thenumber of the SFP/XFPs is different in accordance with the number ofports that can be supported within the same card. The switch isconnected to all of the IF control circuits for the communication of amain signal between arbitrary ports within the apparatus. In addition,the switch, similarly to the IF card, may be included in one card.Accordingly, as a mode of the communication apparatus that has a switch,paths (A), (B), (C), and the like illustrated in FIG. 1 can be set.

In addition, for example, as illustrated in FIG. 2, the communicationapparatus includes a maintenance managing unit and a main signalprocessing unit. Out of these units, the maintenance managing unit, forexample, includes a CPU, a RAM, and a non-volatile memory and performsmonitoring, various settings, and the like of the entire apparatusthrough a control bus by performing overall control thereof.

Meanwhile, the main signal processing unit, for example, includes atransponder card, a muxponder card, an IF card (IF card with SW) havinga SW function, and an IF card connected to a switch. The transpondercard, for example, is a card to which port #1 and port #2 are fixedlyassigned as one-to-one correspondence and which can be connectable onlybetween the ports. The muxponder card is a card that multiplexes areception signal, for example, input from a plurality of ports #3-1 to#3-n (here, n is a natural number) and transmits a resultant signal toport #4 and has a connection destination that is fixedly assigned. Inaddition, there is a case where the muxponder card separates a signalthat is input in the opposite direction, in other words, input from port#4 and transmits resultant signals to ports #3-1 to #3-n. The IF cardhaving the SW function is a card that can freely determine theconnection destination, for example, out of ports #5-1 to #5-4 arrangedinside the card but is not connected to a port of any other card. Inaddition, the IF card connected to the switch performs the same processas that of the card illustrated in FIG. 1.

Functional Blocks of Communication Apparatus

Next, the functional blocks of the communication apparatus according tothe first embodiment will be described with reference to FIG. 3. FIG. 3is a diagram illustrating an example of the functional blocks of thecommunication apparatus according to the first embodiment.

For example, as illustrated in FIG. 3, a communication apparatus 100includes a switch 101, an IF 102, an IF 103, and an IF 104. Out ofthese, the IF 102 is an interface that does not have a SW board, the IF103 is an interface that passes through an SW board, and the IF 104 isan interface that passes through a SW board. In addition, for example,the communication apparatus 100 includes a user interface (UI) 105, acard managing unit 106, an OSPF-TE control unit 107, a topology database(DB) 108, a route calculating unit 109, an RSVP-TE control unit 110, anda non-volatile memory 111.

Out of these, the IF 102 is an example of an IF control circuit such asthe transponder card, the muxponder card, the IF card with SW, or thelike illustrated in FIG. 2. In addition, the switch 101, the IF 103, andthe IF 104 are examples of the IF control circuit that passes through aswitch illustrated in FIG. 1. Furthermore, the processes in the UI 105,the card managing unit 106, the OSPF-TE control unit 107, the routecalculating unit 109, and the RSVP-TE control unit 110 are performed byusing a processor such as the CPU illustrated in FIG. 1 or 2. Inaddition, the topology DB 108 is stored in a memory such as the RAMillustrated in FIG. 1 or 2. Furthermore, the non-volatile memory 111 isan example of the non-volatile memory illustrated in FIG. 1 or 2.

In the IF 102 and the IF 103, for example, as descried with reference toFIGS. 1 and 2, a main signal flows through the switch 101. In addition,in the IF 104, for example, as described with reference to FIGS. 1 and2, a main signal flows not through the switch 101. The IF 102, the IF103, and the IF 104, for example, are connected to an adjacentcommunication apparatus and control communication using a main signalsuch as a data packet or an IP packet for the RSVP-TE or the OSPF-TEcontrol. In addition, the RSVP-TE is a signaling protocol, and theOSPF-TE is a routing protocol.

The UI 105 receives various commands, for example, from a networkmanagement terminal such as an operation system (OPS) that is connectedto the communication apparatus 100. Examples of the various commandsinclude a setting request relating to the IF card such as the switch101, the IF 102, the IF 103, or the IF 104, a request for calculating aroute in a network including the communication apparatus 100, and thelike. In addition, for example, the various commands are used also in acase where a restriction on the transmission route is intentionally setby a user or a case where a restriction is removed. Furthermore, the UI105 informs the network management terminal of information relating tothe IF card such as the switch 101, the IF 102, the IF 103, or the IF104 that is collected by the card managing unit 106.

For example, in a case where a setting request relating to the IF cardis received through the UI 105, the card managing unit 106 notifies theOSPF-TE control unit 107 of the setting request. The setting requestrelating to the IF card is made, for example, in a case where an IF cardis registered or removed. In addition, in the registration of an IFcard, there is also a case where an IF card having a specificrestriction is registered. For example, when the notification isreceived from the card managing unit 106, the OSPF-TE control unit 107generates topology information in accordance with the type of the IFcard, updates the topology DB 108 in which the topology information isstored, and advertises the updated topology information to adjacentcommunication apparatuses. In addition, also in a case where arestriction is set or removed by a user through the card managing unit106, the OSPF-TE control unit 107 generates topology information inaccordance with the setting or removing thereof, updates the topology DB108, and advertises the updated topology information to adjacentcommunication apparatuses. The topology DB 108 stores the topologyinformation such as opaque link-state advertisement (LSA) that includes,for example, a restriction information Sub-type length value (TLV)therein.

In the generation of the topology information, the Opaque LSA includingthe restriction information Sub-TLV is generated. Hereinafter, therestriction information Sub-TLV may be referred to as “Rest Info”. Inaddition, in a case where the topology information advertised by anothercommunication apparatus adjacent thereto is received, the OSPF-TEcontrol unit 107 updates the topology DB 108. Accordingly, in thenetwork including the communication apparatus 100, the same topologyinformation is shared by communication apparatuses.

The configuration of the topology information that is used in thecalculation of a route, which will be described later, is specified inRequest For Comment (RFC) 3630, 4202, 4230, and the like. Here, thetopology information is defined as the Opaque LSA. In the Opaque LSA,various types of information are stored in a format called TLV definedfor the GMPLS so as to respond to the functional expansion.

FIGS. 4A and 4B are diagrams illustrating an example of theconfiguration of the restriction information Sub-TLV. For example, asillustrated in FIG. 4A, the Rest Info is stored in a Sub-TLV acquired byexpanding a vacant portion separately from the Sub-TLVs that are presentunder the Link TLV. In addition, as illustrated in FIG. 4B, the Sub-TLVin which the Rest Info is stored includes “Type” in which a specifiedvalue is used, “Length” that represents the size of the TLV, and “F” and“ID” that are used by a rule specified in accordance with each “Type”value. In addition, as illustrated in FIG. 4B, although the “Length” isset to be “4” or more, the “Length” may be changed in accordance withthe number of types of the “IDs”. Furthermore, “F” is information thatrepresents whether or not a connectable port inside the communicationapparatus 100 is fixed to one, and, for example, “1” is stored thereinin a case where the connectable port is fixed to one, and “0” is storedtherein in a case where there are a plurality of connectable ports. Inaddition, identification information that is used for identifying portsthat can be connectable to each other inside the communication apparatus100 is stored in “ID”. “F” and “ID” will be described in detail later.

The TLV can be arranged in a nested structure, and there is a case where“Router TLV” representing node information and “Link TLV” representinglink information are used. FIG. 5 is a diagram illustrating aconfiguration example of the Opaque LSA. FIG. 6 is a diagramillustrating an overview of the Sub-TLV. For example, as illustrated inFIG. 5, in the Opaque LSA, a router LSA including a “Router TLV” and aLink LSA including a “Link TLV” are present. Out of these, the Link LSAis a set of a plurality of Sub-TLVs and is advertised to nodes withinthe network as one LSA and includes the Rest Info as well. In addition,as illustrated in FIG. 6, in the Sub-TLV, various types of informationrelating to links and nodes are present in sections defined as standard,and the information of the Rest Info is present in a section of anexpanded vacant number. Furthermore, “Traffic Engineering Metric” of aSub-TLV type of “5”, which is illustrated in FIG. 6, is information ofcost values of links used for the route calculation.

Here, the Rest Info that is set in accordance with the type of the IFcard will be described with reference to FIGS. 7A to 13B. FIG. 7A is adiagram illustrating a configuration example of the transponder card.FIG. 7B is a diagram illustrating an example of the restrictioninformation that is set in accordance with the transponder cardillustrated in FIG. 7A.

For example, in the transponder card illustrated in FIG. 7A, a port thatcan be connected for port “#1” to which data is input is port “#2”. Inaddition, in the transponder card illustrated in FIG. 7A, a port thatcan be connected for port “#2” to which data can be connected is port“#1”. In such a case, the OSPF-TE control unit 107, as illustrated inFIG. 7B, in the setting of the Rest Info, stores port “#1”, F Bit “1”,and ID “0x01” in association with one another. In addition, the OSPF-TEcontrol unit 107 stores port “#2”, F Bit “1”, and ID “0x01” are storedin association with one another. In other words, the Rest Infoillustrated in FIG. 7B represents that a connectable port of port “#1”is fixed to one, and the connectable port is a port that has an ID of“0x01”. Similarly, it is represented that a connectable port of port“#2” is fixed to one, and the connectable port is a port that has an IDof “0x01”.

FIG. 8A is a diagram illustrating a configuration example of a muxpondercard. FIG. 8B is a diagram illustrating an example of the restrictioninformation that is set in accordance with the muxponder cardillustrated in FIG. 8A. Since the IF card described with reference toFIGS. 7A and 7B is included in FIGS. 8A and 8B, the description thereofwill not be repeated here.

For example, in the muxponder card illustrated in FIG. 8A, a connectableport for port “#3-1”, “#3-2”, “#3-3”, or “#3-4” to which data is inputis port “#4”. In addition, in the muxponder card illustrated in FIG. 8A,a connectable port for port “#4” to which data is input is any one ofports “#3-1”, “#3-2”, “#3-3”, and “#3-4”. In conclusion, in themuxponder card illustrated in FIG. 8A, ports, in which a plurality ofports as multiplexing sources and a port as a multiplexing destinationcan be connected so as to have the “n-to-1” relation, are fixed.Described in detail, “ports #3-1” to “#3-4” are fixedly connected toports “#4-1” to “#4-4”. In such a case, the OSPF-TE control unit 107, asillustrated in FIG. 8B, in setting of the Rest Info, stores port “#3-1”,F Bit “1”, and ID “0x02 (0b00010)” in association with one another. Inaddition, the OSPF-TE control unit 107, stores port “#3-2”, F Bit “1”,and ID “0x04 (0b00100)” in association with one another. Furthermore,the OSPF-TE control unit 107 stores port “#3-3”, F Bit “1”, and ID “0x08(0b01000)” in association with one another. In addition, the OSPF-TEcontrol unit 107 stores port “#3-4”, F Bit “1”, and ID “0x10 (0b10000)”in association with one another. Furthermore, the OSPF-TE control unit107 stores port “#4”, F Bit “1”, and ID “0x1E (0b11110)” in associationwith one another. In other words, the OSPF-TE control unit 107 assignsunique IDs to a plurality of ports as the multiplexing sources insidethe communication apparatus 100 and assigns a value acquired bycalculating OR of all the ID values set to the multiplexing sources tothe port as the multiplexing destination. In addition, as describedabove, since port #4, that is, ports #4-1 to #4-4, described in detail,are fixedly connected to ports “#3-1” to “#3-4”, “1” is assigned to theF Bits. Furthermore, since ID “0x01” is used in ports “#1” and “#2”, theOSPF-TE control unit 107 uses IDs “0x02”, “0x04”, “0x08”, and “0x10”.Although “0x01”, “0x02”, “0x03”, . . . may be used for the IDs, by using“0x02”, “0x04”, . . . for the IDs in consideration of the bit, it can berepresented that a plurality of ports can be connected to one port.

In other words, in the Rest Info illustrated in FIG. 8B, port “#3-1” isrepresented that the number of connectable ports is fixed to one, andthe connectable port is a port that has “1” at the same bit position asthat of “1” in ID “0b00010”. Similarly, port “#3-2” is represented thatthe number of connectable ports is fixed to one, and the connectableport is a port that has “1” at the same bit position as that of “1” inID “0b00100”. Similarly, port “#3-3” is represented that the number ofconnectable ports is fixed to one, and the connectable port is a portthat has “1” at the same bit position as that of “1” in ID “0b01000”.Similarly, port “#3-4” is represented that the number of connectableports is fixed to one, and the connectable port is a port that has “1”at the same bit position as that of “1” in ID “0b10000”. Similarly, port“#4” is represented that the number of connectable ports is fixed toone, and the connectable port is a port that has “1” at the same bitposition as that of “1” in ID “0b11110”.

FIG. 9A is a diagram illustrating a configuration example of a muxpondercard in which a SW, in which a connection destination is restricted, isbuilt. FIG. 9B is a diagram illustrating an example of the restrictioninformation that is set in accordance with the muxponder cardillustrated in FIG. 9A. Since the IF card described with reference toFIGS. 7A and 7B is included in FIGS. 9A and 9B, the description thereofwill not be repeated here.

For example, in the muxponder card illustrated in FIG. 9A, a connectableport for port “#3-1”, “#3-2”, “#3-3”, or “#3-4” to which data is inputis port “#4-1”, “#4-2”, “#4-3”, or “#4-4”. In addition, in the muxpondercard illustrated in FIG. 9A, a connectable port for port “#4-1”, “#4-2”,“#4-3”, or “#4-4” to which data is input is port “#3-1”, “#3-2”, “#3-3”,or “#3-4”. In conclusion, in the muxponder card illustrated in FIG. 9A,a plurality of ports are present as the multiplexing destinations for aplurality of ports as multiplexing sources, and the connections arechanged by the SW, but the connection destination is restricted. In sucha case, the OSPF-TE control unit 107, as illustrated in FIG. 9B, insetting of the Rest Info, stores port “#3-1”, F Bit “0”, and ID “0x02(0b00010)” in association with one another. In addition, the OSPF-TEcontrol unit 107 stores port “#3-2”, F Bit “0”, and ID “0x04 (0b00100)”in association with one another. Furthermore, the OSPF-TE control unit107 stores port “#3-3”, F Bit “0”, and ID “0x08 (0b01000)” inassociation with one another. In addition, the OSPF-TE control unit 107stores port “#3-4”, F Bit “0”, and ID “0x10 (0b10000)” in associationwith one another. Furthermore, the OSPF-TE control unit 107 stores port“#4”, F Bit “0”, and ID “0x1E (0b11110)” in association with oneanother. In other words, in the OSPF-TE control unit 107, it isrepresented that the connection destination is not fixed to one bysetting the F Bit to “0”, and a connection destination as a multiplexingdestination can be selected.

In other words, in the Rest Info illustrated in FIG. 9B, port “#3-1” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having “1” at the same bit position as “1”in ID “0b00010”. Similarly, port “#3-2” is represented that there are aplurality of connectable ports, and the connectable ports are portshaving “1” at the same bit position as “1” in ID “0b00100”. Similarly,port “#3-3” is represented that there are a plurality of connectableports, and the connectable ports are ports having “1” at the same bitposition as “1” in ID “0b01000”. Similarly, port “#3-4” is representedthat there are a plurality of connectable ports, and the connectableports are ports having “1” at the same bit position as “1” in ID“0b10000”. Similarly, port “#4” is represented that there are aplurality of connectable ports, and the connectable ports are portshaving “1” at the same bit position as “1” in ID “0b11110”.

FIG. 10A is a diagram illustrating a configuration example of an IF cardin which a SW is built. FIG. 10B is a diagram illustrating an example ofthe restriction information that is set in accordance with the IF cardillustrated in FIG. 10A. Since the IF card described with reference toFIGS. 7A to 8B is included in FIGS. 10A and 10B, the description thereofwill not be repeated here.

For example, in the IF card illustrated in FIG. 10A, connectable portsfor port “#5”, “#6”, “#7”, or “#8” to which data is input are portsother than the input port. In such a case, the OSPF-TE control unit 107,as illustrated in FIG. 10B, in setting of the Rest Info, stores port“#5”, F Bit “0”, and ID “0x20” in association with one another. Inaddition, the OSPF-TE control unit 107 stores port “#6”, F Bit “0”, andID “0x20” in association with one another. Furthermore, the OSPF-TEcontrol unit 107 stores port “#7”, F Bit “0”, and ID “0x20” inassociation with one another. In addition, the OSPF-TE control unit 107stores port “#8”, F Bit “0”, and ID “0x20” in association with oneanother.

In other words, in the Rest Info illustrated in FIG. 10B, port “#5” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x20”. Similarly, port “#6” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x20”. Similarly, port “#7” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x20”. Similarly, port “#8” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x20”.

FIG. 11A is a diagram illustrating a configuration example of an IF cardthat passes through a SW card. FIG. 11B is a diagram illustrating anexample of the restriction information that is set in accordance withthe IF card illustrated in FIG. 11A. Since the IF card described withreference to FIGS. 7A to 8B, 10A, and 10B is included in FIGS. 11A and11B, the description thereof will not be repeated here.

For example, in the IF card illustrated in FIG. 11A, connectable portsfor port “#9”, “#10”, “#11”, or “#12” to which data is input are portsother than the input port by passing through the SW card. In such acase, the OSPF-TE control unit 107, as illustrated in FIG. 11B, insetting of the Rest Info, stores port “#9”, F Bit “0”, and ID “0x40” inassociation with one another. In addition, the OSPF-TE control unit 107stores port “#10”, F Bit “0”, and ID “0x40” in association with oneanother. Furthermore, the OSPF-TE control unit 107 stores port “#11”, FBit “0”, and ID “0x40” in association with one another. In addition, theOSPF-TE control unit 107 stores port “#12”, F Bit “0”, and ID “0x40” inassociation with one another.

In other words, in the Rest Info illustrated in FIG. 11B, port “#9” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”. Similarly, port “#10” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”. Similarly, port “#11” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”. Similarly, port “#12” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”.

FIG. 12A is a diagram illustrating a configuration example of an IFcard, which has a restriction, passing through a SW card. FIG. 12B is adiagram illustrating an example of the restriction information that isset in accordance with the IF card illustrated in FIG. 12A.

For example, in the IF card illustrated in FIG. 12A, by passing throughthe SW card, connectable ports for port “#1”, “#2”, “#3”, or “#4” towhich data is input are ports other than the input port. In addition, inthe IF card illustrated in FIG. 12A, by passing through the SW card,connectable ports for port “#5”, “#6”, “#7”, or “#8” to which data isinput are ports other than the input port. In conclusion, the reason whythere is a restriction is, for example, due to the employment of asystem in which a chassis that houses a plurality of cards therein isexpanded, and the plurality of chassis are managed as one node. Asabove, in a case where the plurality of chassis are managed as one node,connectable ports are set in units of chassis.

In such a case, the OSPF-TE control unit 107, as illustrated in FIG.12B, in setting of the Rest Info, stores port “#1”, F Bit “0”, and ID“0x01” in association with one another. In addition, the OSPF-TE controlunit 107 stores port “#2”, F Bit “0”, and ID “0x01” in association withone another. Furthermore, the OSPF-TE control unit 107 stores port “#3”,F Bit “0”, and ID “0x01” in association with one another. In addition,the OSPF-TE control unit 107 stores port “#4”, F Bit “0”, and ID “0x01”in association with one another. Furthermore, the OSPF-TE control unit107 stores port “#5”, F Bit “0”, and ID “0x02” in association with oneanother. In addition, the OSPF-TE control unit 107 stores port “#6”, FBit “0”, and ID “0x02” in association with one another. Furthermore, theOSPF-TE control unit 107 stores port “#7”, F Bit “0”, and ID “0x02” inassociation with one another. In addition, the OSPF-TE control unit 107stores port “#8”, F Bit “0”, and ID “0x02” in association with oneanother.

In other words, in the Rest Info illustrated in FIG. 12B, port “#1” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x01”. Similarly, port “#2” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x01”. Similarly, port “#3” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x01”. Similarly, port “#4” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x01”. Similarly, port “#5” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x02”. Similarly, port “#6” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x02”. Similarly, port “#7” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x02”. Similarly, port “#8” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x02”.

FIG. 13A is a diagram illustrating a configuration example of the IFcard in a case where the IF card having the SW illustrated in FIG. 11Abuilt therein is removed. FIG. 13B is a diagram illustrating an exampleof the restriction information that is set in accordance with the IFcard illustrated in FIG. 13A. Since the IF card described with referenceto FIGS. 7A and 8B is included in FIGS. 13A and 13B, the descriptionthereof will not be repeated here.

For example, in the IF card illustrated in FIG. 13A, connectable portsfor port “#5”, “#6”, “#7”, “#8”, “#9”, “#10”, “#11”, or “#12” to whichdata is input are ports other than the input port. In such a case, theOSPF-TE control unit 107, as illustrated in FIG. 13B, in setting of theRest Info, stores port “#5”, F Bit “0”, and ID “0x40” in associationwith one another. In addition, the OSPF-TE control unit 107 stores port“#6”, F Bit “0”, and ID “0x40” in association with one another.Furthermore, the OSPF-TE control unit 107 stores port “#7”, F Bit “0”,and ID “0x40” in association with one another. In addition, the OSPF-TEcontrol unit 107 stores port “#8”, F Bit “0”, and ID “0x40” inassociation with one another. Furthermore, the OSPF-TE control unit 107stores port “#9”, F Bit “0”, and ID “0x40” in association with oneanother. In addition, the OSPF-TE control unit 107 stores port “#10”, FBit “0”, and ID “0x40” in association with one another. Furthermore, theOSPF-TE control unit 107 stores port “#11”, F Bit “0”, and ID “0x40” inassociation with one another. In addition, the OSPF-TE control unit 107stores port “#12”, F Bit “0”, and ID “0x40” in association with oneanother. In conclusion, the OSPF-TE control unit 107 updates ID “0x20”of ports “#5” to “#8” with “0x40”.

In other words, in the Rest Info illustrated in FIG. 13B, port “#5” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”. Similarly, port “#6” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”. Similarly, port “#7” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”. Similarly, port “#8” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”. Similarly, port “#9” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”. Similarly, port “#10” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”. Similarly, port “#11” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”. Similarly, port “#12” isrepresented that there are a plurality of connectable ports, and theconnectable ports are ports having ID “0x40”.

Referring back to FIG. 3, the OSPF-TE control unit 107, for example,receives a restriction setting made by a user through the networkmanagement terminal, the UI 105, and the card managing unit 106. Then,the OSPF-TE control unit 107 sets the ID information of the receivedport as the Rest Info and sets the F Bit to “1” in a case where theconnection destination is fixed to one. At this time, in a case wherethere is any other port to which the same ID has been assigned, a changein the connectable ports occurs, and accordingly, the OSPF-TE controlunit 107 sets the F Bit in accordance with the change, and re-advertisesthe changed topology information. On the other hand, in a case wherethere is no other port to which the same ID has been assigned, theOSPF-TE control unit 107 advertises the topology information in which arestriction is newly set.

In addition, the OSPF-TE control unit 107, for example, receives arestriction releasing setting made by a user through the networkmanagement terminal, the UI 105, and the card managing unit 106. Then,the OSPF-TE control unit 107 removes the Rest Info corresponding to thereceived port information. At this time, in a case where there is a portto which the same ID as the ID of the removed port has been assigned,there is a change in the connectable port, and accordingly, the OSPF-TEcontrol unit 107 sets the F Bit in accordance with the change andre-advertises the changed topology information. On the other hand, in acase where there is no other port to which the same ID has beenassigned, the OSPF-TE control unit 107 advertises the topologyinformation from which the restriction is removed.

When a route calculation request, in which the start port and the endport are designated, is received from the network management terminal,for example, through the UI 105, the route calculating unit 109calculates the route while referring to the topology DB 108 and notifiesthe RSVP-TE control unit 110 of a calculation result. In the routecalculation performed by the route calculating unit 109, the F Bitincluded in the Rest Info may not be used. The route calculation will bedescribed in detail later.

The RSVP-TE control unit 110 performs a signaling protocol operationfrom the start node to the end node as end-to-end based on thecalculation result of a route, for example, notified from the routecalculating unit 109. Accordingly, the RSVP-TE control unit 110 sets theIF, the switch, and the like in each communication apparatus for thecommunication of a main signal. In addition, the RSVP-TE control unit110 stores a route used in signaling, information relating to thesignaling, and the like in the non-volatile memory 111. The storing ofthe route used in the signaling and the information relating to thesignaling in the non-volatile memory 111 is performed for the recoveryat the time of restarting the communication apparatus 100. Thenon-volatile memory 111, for example, stores the route used in thesignaling and the information relating to the signaling therein.

Route Calculation

Next, the calculation of a route using the Rest Info will be describedwith reference to FIGS. 14 to 18. FIG. 14 is a diagram illustrating anexample of route calculation in a case where the start and end portshave F Bits of “1”. Here, a value written near each port in FIG. 14represents the Rest Info “ID (F Bit)” of the port. In addition, a valuewritten in each route that connects ports of nodes represents a costvalue. Here, ports “#1” and “#2” of Node A and Node D illustrated inFIG. 14 are assumed to be transponder cards. In addition, ports “#3-1”to “#3-4” and “#4” of Node A and Node D illustrated in FIG. 14 areassumed to be muxponder cards. FIG. 14 illustrates a case where, in anetwork including a communication apparatus from Node A to Node D, arequest for calculating a route, of which the start point is port “#1”of Node A and the end point is port “#1” of Node D, is received by NodeA.

For example, as illustrated in FIG. 14, Node A that has received therequest for calculating a route from the network management terminalrecognizes that an F Bit of “1” is assigned to port “#1” of Node A andport “#1” of Node D by referring to the topology DB 108. Then, Node Asearches for a port to which the same ID as that of port “#1” of Node Ais assigned within Node A and, as a result of the search, performs“Include designation” of port “#2” of Node A. In addition, Node Asearches for a port to which the same ID as that of port “#1” of Node Dis assigned within Node D and, as a result of the search, performs“Include designation” of port “#2” of Node D. In addition, the “Includedesignation” is denoted by a black circle in FIG. 14.

Subsequently, Node A recognizes that the connection destination node ofport “#2” of Node A is Node B, and the port is port “#1” of Node B, byreferring to the topology DB 108. In addition, Node A recognizes thatthe connection destination node of port “#2” of Node D is Node B, andthe port is port “#3” of Node B, by referring to the topology DB 108.Here, since there is no restriction on ports “#1” and “#3” of Node B,Node A calculates a route of which the start point is port “#1 of Node Band the end point is port “#3” of Node B by excluding the ports of“Include designation”. In other words, Node A outputs a result ofcalculation of a route in order of “ports “#1” and “#2” of Node A”,“ports “#1” and “#3” of Node B”, and “ports “#2” and “#1” of Node D”.Here, the result of the route calculation is denoted by a dotted arrowin FIG. 14.

FIG. 15 is a diagram illustrating an example of route calculation in acase where ports having F Bits of “1” are continuous. Here, a valuewritten near each port in FIG. 15 represents the Rest Info “ID (F Bit)”of the port. In addition, a value written in each route that connectsports of nodes represents a cost value. Here, ports “#1” and “#2” ofNode A and Node H illustrated in FIG. 15 are assumed to be transpondercards. In addition, ports “#3-1” to “#3-4” and “#4” of Node A and Node Hillustrated in FIG. 15 are assumed to be muxponder cards. Furthermore,ports “#1” and “#3” and ports “#2” and “#4” of Node D illustrated inFIG. 15 are cards that are physically different from each other, and achassis housing a plurality of cards is assumed to be expanded. FIG. 15illustrates a case where, in a network including a communicationapparatus from Node A to Node H, a request for calculating a route, ofwhich the start point is port “#1” of Node A and the end point is port“#1” of Node H, is received by Node A.

For example, as illustrated in FIG. 15, Node A that has received therequest for calculating a route from the network management terminalrecognizes that an F Bit of “1” is assigned to port “#1” of Node A andport “#1” of Node H by referring to the topology DB 108. Then, Node Asearches for a port to which the same ID as that of port “#1” of Node Ais assigned within Node A and, as a result of the search, performs“Include designation” of port “#2” of Node A. In addition, Node Asearches for a port to which the same ID as that of port “#1” of Node His assigned within Node H and, as a result of the search, performs“Include designation” of port “#2” of Node H. Subsequently, Node Arecognizes that the connection destination node of port “#2” of Node His Node D, the port is port “#3” of Node D, and an F Bit of “1” isassigned thereto by referring to the topology DB 108. Thereafter, Node Asearches for a port to which the same ID as that of port “#3” of Node Dis assigned within Node D and, as a result of the search, performs“Include designation” of port “#1” of Node D. In addition, the “Includedesignation” is denoted by a black circle in FIG. 15.

Then, Node A recognizes that the connection destination node of port“#1” of Node D is Node C, and the port is port “#3” of Node C, byreferring to the topology DB 108. Here, since there is no restriction onport “#3” of Node C and port “#1” of Node B, Node A calculates a routeof which the start point is port “#1 of Node B and the end point is port“#3” of Node C by excluding the ports of “Include designation”. Node Aselects a route having a smaller cost value in the route calculationfrom port “#1” of Node B to port “#3” of Node C in which there is norestriction. In other words, Node A outputs a result of calculation of aroute in order of “ports “#1” and “#2” of Node A”, “ports “#1” and “#4”of Node B”, “ports “#2” and “#3” of Node C”, “ports “#1” and “#3” ofNode D”, and “ports “#2” and “#1” of Node H”. Here, the result of theroute calculation is denoted by a dotted arrow in FIG. 15.

FIG. 16 is a diagram illustrating an example of route calculation in acase where a muxponder card is an end point. Here, a value written neareach port in FIG. 16 represents the Rest Info “ID (F Bit)” of the port.In addition, a value written in each route that connects ports of nodesrepresents a cost value. Here, ports “#1” and “#2” of Node A and Node Dillustrated in FIG. 16 are assumed to be transponder cards. In addition,ports “#3-1” to “#3-4” and “#4” of Node A and Node D illustrated in FIG.16 are assumed to be muxponder cards. FIG. 16 illustrates a case where,in a network including a communication apparatus from Node A to Node D,a request for calculating a route, of which the start point is port “#1”of Node A and the end point is port “#3-1” of Node D, is received byNode A.

For example, as illustrated in FIG. 16, Node A that has received therequest for calculating a route from the network management terminalrecognizes that an F Bit of “1” is assigned to port “#1” of Node A andport “#3-1” of Node D by referring to the topology DB 108. Then, Node Asearches for a port to which the same ID as that of port “#1” of Node Ais assigned within Node A and, as a result of the search, performs“Include designation” of port “#2” of Node A. In addition, Node Asearches for port “#4” to which the same ID as that of port “#3-1” ofNode D is connectable in Node D and, as a result of the search, performs“Include designation” of port “#4” of Node D. In addition, the “Includedesignation” is denoted by a black circle in FIG. 16.

Subsequently, Node A recognizes that the connection destination node ofport “#1” of Node A is Node B, and the port is port “#1” of Node B, byreferring to the topology DB 108. In addition, Node A recognizes thatthe connection destination node of port “#4” of Node D is Node B, andthe port is port “#4” of Node B, by referring to the topology DB 108.Here, since there is no restriction on ports “#1” and “#4” of Node B,Node A calculates a route of which the start point is port “#1 of Node Band the end point is port “#4” of Node B by excluding the ports of“Include designation”. In other words, Node A outputs a result ofcalculation of a route in order of “ports “#1” and “#2” of Node A”,“ports “#1” and “#4” of Node B”, and “ports “#4” and “#3-1” of Node D”.Here, the result of the route calculation is denoted by a dotted arrowin FIG. 16.

FIG. 17 is a diagram illustrating an example of route calculation in acase where an F Bit is not used. Here, a value written near each port inFIG. 17 represents the Rest Info “ID (F Bit)” of the port. In thedescription presented with reference to FIG. 17, calculation of a routenot using an F Bit will be described. In addition, a value written ineach route that connects ports of nodes represents a cost value. Here,ports “#3” and “#4” of Node A and Node D illustrated in FIG. 17 areassumed to be transponder cards. Similarly, ports “#1” and “#4” of NodeB illustrated in FIG. 17 are assumed to be transponder cards. FIG. 17illustrates a case where, in a network including a communicationapparatus from Node A to Node D, a request for calculating a route, ofwhich the start point is port “#5” of Node A and the end point is port“#5” of Node D, is received by Node A.

For example, as illustrated in FIG. 17, Node A acquires ports “#6”,“#7”, and “#8” that can be connected to port “#5” of Node A by referringto the topology DB 108. Here, it is assumed that Node A selects port“#7” out of ports “#7” and “#8” of Node A that have the same cost value.Then, Node A recognizes that the connection destination node of port“#7” of Node A is Node B, and the port is port “#3” of Node B, byreferring to the topology DB 108.

Subsequently, Node A acquires ports “#5” and “#6” that can be connectedto port “#3” of Node B by referring to the topology DB 108. Here, Node Aselects port “#5” of Node B having a smaller cost value out of ports“#5” and “#6” of Node B. Thereafter, Node A recognizes that theconnection destination node of port “#5” of Node B is Node D, and theport is port “#4” of Node D, by referring to the topology DB 108.

Then, since port “#5” as the end point is present in Node D, Node Adetermines whether or not ports “#4” and “#5” of Node D can be connectedto each other by referring to the topology DB 108. At this time, sincethe IDs of ports “#4” and “#5” of Node D are different from each other,Node A recognizes that a route (A) illustrated in FIG. 17 is notconnectable.

Thus, Node A recalculates from port “#3” of Node B that is acquired byreturning backward by one hop. In the recalculation, Node A selects port“#6” that can be connected to port “#3” of Node B. Then, Node Arecognizes that the connection destination node of port “#6” of Node Bis Node D, and the port is port “#7” of Node D by referring to thetopology DB 108.

Subsequently, since port “#5” as the end point is present in Node D,Node A determines whether or not ports “#7” and “#5” of Node D can beconnected to each other by referring to the topology DB 108. At thistime, since the IDs of ports “#7” and “#5” of Node D are the same, NodeA outputs a route (B) illustrated in FIG. 17 as a calculation result. Inother words, Node A outputs the calculation result of a route in orderof “ports “#5” and “#7” of Node A”, “ports “#3” and “#6” of Node B”, and“ports “#7” and “#5” of Node D”.

FIG. 18 is a diagram illustrating an example of route calculation in acase where an F Bit is not used. Here, a value written near each port inFIG. 18 represents the Rest Info “ID (F Bit)” of the port. In thedescription presented with reference to FIG. 18, calculation of a routenot using an F Bit will be described. In addition, a value written ineach route that connects ports of nodes represents a cost value. Here,ports “#3” and “#4” of Node A illustrated in FIG. 18 are assumed to betransponder cards. Similarly, ports “#1” and “#4” of Node B illustratedin FIG. 18 are assumed to be transponder cards. In addition, ports “#3”,“#4”, and “#7” of Node D illustrated in FIG. 18 are assumed to be IFcards in which a SW is built, IF cards that pass through a SW card, orthe like. FIG. 18 illustrates a case where, in a network including acommunication apparatus from Node A to Node D, a request for calculatinga route, of which the start point is port “#5” of Node A and the endpoint is port “#5” of Node D, is received by Node A.

For example, as illustrated in FIG. 18, Node A acquires ports “#6”,“#7”, and “#8” that can be connected to port “#5” of Node A by referringto the topology DB 108. Here, it is assumed that Node A selects port“#7” out of ports “#7” and “#8” of Node A that have the same cost value.Then, Node A recognizes that the connection destination node of port“#7” of Node A is Node B, and the port is port “#3” of Node B, byreferring to the topology DB 108.

Subsequently, Node A acquires ports “#5” and “#6” that can be connectedto port “#3” of Node B by referring to the topology DB 108. Here, Node Aselects port “#5” of Node B having a smaller cost value out of ports“#5” and “#6” of Node B. Thereafter, Node A recognizes that theconnection destination node of port “#5” of Node B is Node D, and theport is port “#4” of Node D, by referring to the topology DB 108.

Then, since port “#5” as the end point is present in Node D, Node Adetermines whether or not ports “#4” and “#5” of Node D can be connectedto each other by referring to the topology DB 108. At this time, sincethe IDs of ports “#4” and “#5” of Node D are different from each other,Node A recognizes that a route (A) illustrated in FIG. 18 is notconnectable.

Thus, Node A recalculates from port “#3” of Node B that is acquired byreturning backward by one hop. In the recalculation, Node A selects port“#6” that can be connected to port “#3” of Node B. Then, Node Arecognizes that the connection destination node of port “#6” of Node Bis Node D, and the port is port “#7” of Node D by referring to thetopology DB 108.

Subsequently, since port “#5” as the end point is present in Node D,Node A determines whether or not ports “#7” and “#5” of Node D can beconnected to each other by referring to the topology DB 108. At thistime, since the IDs of ports “#7” and “#5” of Node D are different fromeach other, Node A recognizes that a route (B) illustrated in FIG. 18 isnot connectable.

Thus, Node A recalculates from port “#5” of Node A that is acquired byreturning backward by one hop further. In the recalculation, Node Aselects port “#8” that can be connected to port “#5” of Node A. Then,Node A recognizes that the connection destination node of port “#8” ofNode A is Node C, and the port is port “#1” of Node C by referring tothe topology DB 108.

Subsequently, Node A selects port “#2” that can be connected to port“#1” of Node C. Thereafter, Node A recognizes that the connectiondestination node of port “#2” of Node C is Node D, and the port is port“#8” of Node D by referring to the topology DB 108.

Then, since port “#5” as the end point is present in Node D, Node Adetermines whether or not ports “#8” and “#5” of Node D can be connectedto each other by referring to the topology DB 108. At this time, sincethe IDs of ports “#8” and “#5” of Node D are the same, Node A outputs aroute (C) illustrated in FIG. 18 as a calculation result. In otherwords, Node A outputs the calculation result of a route in order of“ports “#5” and “#8” of Node A”, “ports “#1” and “#2” of Node C”, and“ports “#8” and “#5” of Node D”.

Topology Information Setting Process

Next, a topology information setting process at the time of setting anIF card according to the first embodiment will be described withreference to FIG. 19. FIG. 19 is a flowchart illustrating an example ofthe flow of the topology information setting process at the time ofsetting the IF card according to the first embodiment.

For example, as illustrated in FIG. 19, the communication apparatus 100receives a request for setting an IF card from the network managementterminal in Step S101. Then, the communication apparatus 100 determinesthe card type of the IF card included in the communication apparatus 100in Step S102. At this time, in a case where the card type is atransponder card, the communication apparatus 100 assigns the same IDthat is unique inside the communication apparatus 100 to each portincluded in the transponder card in Step S103. Thereafter, thecommunication apparatus 100 sets “1” to the F Bit in Step S104.

On the other hand, in a case where the card type is a muxponder card,the communication apparatus 100 assigns IDs that are unique inside thecommunication apparatus 100 to a plurality of ports as multiplexingsources of the muxponder card in Step S105. Then, the communicationapparatus 100 assigns a value acquired by calculating OR of IDs set asthe multiplexing sources to the port as the multiplexing destination ofthe muxponder card in Step S106. Thereafter, the communication apparatus100 sets “1” to the F Bit in Step S107.

In addition, in a case where the card type is an IF card in which a SWboard is built, the communication apparatus 100 assigns the same ID thatis unique inside the communication apparatus 100 to each port includedin the IF card in Step S108. Thereafter, the communication apparatus 100sets “0” to the F Bit in Step S109.

On the other hand, in a case where the card type is a general IF card,the communication apparatus 100 assigns an ID that is the same for theIF cards and is unique inside the communication apparatus 100 in StepS110. Then, the communication apparatus 100 sets “0” to the F Bit inStep S111. Thereafter, the communication apparatus 100 generates anOpaque LSA including Rest Info in which the F Bit and the ID are set andadvertises the generated Opaque LSA to adjacent communicationapparatuses in Step S112.

Next, a topology information setting process at the time of removing anIF card according to the first embodiment will be described withreference to FIG. 20. FIG. 20 is a flowchart illustrating an example ofthe flow of the topology information setting process at the time ofremoving an IF card according to the first embodiment.

For example, as illustrated in FIG. 20, the communication apparatus 100receives a request for removing an IF card from the network managementterminal in Step S201. Then, the communication apparatus 100 removes theOpaque LSA including the Rest Info of the corresponding IF card andchanges the Rest Info of other IF cards that occur due to the removal inStep S202. In addition, the communication apparatus 100 advertises theOpaque LSA including the Rest Info after the update to adjacentcommunication apparatuses.

Next, a topology information setting process at the time of changing anIF card according to the first embodiment will be described withreference to FIG. 21. FIG. 21 is a flowchart illustrating an example ofthe flow of the topology information setting process at the time ofchanging an IF card according to the first embodiment. FIG. 21illustrates a process in a case where a restriction that is originallyincluded in an IF card is released due to the revision of hardware orthe like.

For example, as illustrated in FIG. 21, the communication apparatus 100receives a request for changing an IF card from the network managementterminal in Step S301. Then, the communication apparatus 100 updates theID of the IF card with an ID that is assigned to a general IF card inStep S302. Subsequently, the communication apparatus 100 re-advertisesthe Opaque LSA including the Rest Info to the adjacent communicationapparatuses in Step S303.

Next, a topology information setting process at the time of changing arestriction according to the first embodiment will be described withreference to FIG. 22. FIG. 22 is a flowchart illustrating an example ofthe flow of the topology information setting process at the time ofchanging a restriction according to the first embodiment. FIG. 22illustrates a case where an intended restriction of a port is set orremoved by a user.

For example, as illustrated in FIG. 22, the communication apparatus 100receives a notification for setting or removing an ID of a port from thenetwork management terminal in Step S401. Then, the communicationapparatus 100 determines whether or not the received notification is anotification used for setting an ID in Step S402. At this time, in acase where the received notification is the notification used forsetting an ID (Yes in Step S402), the communication apparatus 100 setsthe ID information to a target port and sets “1” to the F Bit in a casewhere a connectable port is fixed in Step S403.

In addition, when there are a plurality of connectable ports in a casewhere the port having the same ID is already present, the communicationapparatus 100 sets the F Bit to “0” in a case where there is a pluralityof connectable ports and sets the F Bit to “1” in a case where theconnectable port is fixed to one and advertises the changed Opaque LSAin Step S404. In addition, the communication apparatus 100 re-advertisesthe Opaque LSA to which the Rest Info of the port of which the ID hasbeen newly set in Step S405.

On the other hand, when there is any other port to which the same ID isassigned in a case where the received notification is a notificationused for removing an ID (No in Step S402), the communication apparatus100 updates the F Bit of the other port in accordance with theconnection state in Step S406. In other words, the communicationapparatus 100 updates the F Bit to “0” in a case where there are aplurality of connectable ports and updates the F Bit to “1” in a casewhere the connectable port is fixed to one and re-advertises the OpaqueLSA in a case where there is a change in the F Bit. In addition, thecommunication apparatus 100 re-advertises the Opaque LSA from which theRest Info of the port, of which the ID has been removed, is removed inStep S407.

Route Calculating Process

Next, a process of reflecting the restriction item according to thefirst embodiment on route calculation will be described with referenceto FIG. 23. FIG. 23 is a flowchart illustrating an example of the flowof the process of reflecting the restriction item according to the firstembodiment on the route calculation.

For example, as illustrated in FIG. 23, the communication apparatus 100receives a route calculating request from the network managementterminal in Step S501. In the route calculating request, information ofdesignated start and end ports and the like is included. Then, thecommunication apparatus 100 determines whether or not the F Bit of thedesignated start port is “1” by referring to the topology DB 108 in StepS502. At this time, in a case where the F Bit of the start port is “1”(Yes in Step S502), the communication apparatus 100 searches for a portthat can be connected to the start port in Step S503. Then, thecommunication apparatus 100 performs “Include designation” of theretrieved port in Step S504. Subsequently, the communication apparatus100 searches for a port of the communication apparatus that opposes theretrieved port by referring to the topology DB 108 in Step S505.Thereafter, the communication apparatus 100 determines whether or notthe F Bit of the opposing port of the communication apparatus is “1” inStep S506. At this time, in a case where the F Bit is “1” (Yes in StepS506), the communication apparatus 100 performs the process of S503 inwhich a connectable port is further searched.

On the other hand, in a case where the F Bit is “0” (No in Step S506),the communication apparatus 100 determines whether the F Bit of thedesignated end port is “1” by referring to the topology DB 108 in StepS507. At this time, in a case where the F Bit of the end port is “1”(Yes in Step S507), the communication apparatus 100 searches for a portthat can be connected to the end port in Step S508. Then, thecommunication apparatus 100 performs “Include designation” of theretrieved port in Step S509. Subsequently, the communication apparatus100 searches for a port of the communication apparatus that opposes theretrieved port by referring to the topology DB 108 in Step S510.Thereafter, the communication apparatus 100 determines whether or notthe F Bit of the opposing port of the communication apparatus is “1” inStep S511. At this time, in a case where the F Bit is “1” (Yes in StepS511), the communication apparatus 100 performs the process of Step S508in which a connectable port is further searched.

On the other hand, in a case where the F Bit is “0” (No in Step S511),the communication apparatus 100 performs route calculation for a routethat is positioned on the inner side of a portion that has beendesignated through “Include designation” in Step S512. Then, thecommunication apparatus 100 outputs a route acquired by combining theroute for which the route calculation has been performed and the portthat has been designated through “Include designation” as a result ofthe route calculation in Step S513. In addition, in a case where the FBit of the start port is “0” (No in Step S502), the communicationapparatus 100 performs the process of Step S507. In addition, in a casewhere the F Bit of the end port is “0” (No in Step S507), thecommunication apparatus 100 performs the process of Step S512.Furthermore, in a case where the F Bits of the start and end ports are“0” or the Rest Info has not been assigned, the communication apparatus100 does not perform “Include designation”.

Next, a route calculating process according to the first embodiment willbe described with reference to FIG. 24. FIG. 24 is a flowchartillustrating an example of the route calculating process according tothe first embodiment.

For example, as illustrated in FIG. 24, in a case where the routecalculation is performed, the communication apparatus 100 acquires theOpaque LSA of a port as a route searching source from the topology DB108 in Step S601. Then, the communication apparatus 100 determineswhether or not the port as the route searching source is a port locatedinside the communication apparatus including the end port in Step S602.At this time, in a case where the port is determined not to be a portinside the communication apparatus including the end port (No in StepS602), the communication apparatus 100 determines whether or not RestInfo has been assigned to the port as the route searching source insidethe Opaque LSA in Step S603.

In a case where the Rest Info has not been assigned to the port as theroute searching source (No in Step S603), there is no restriction on theconnection destination, and accordingly, the communication apparatus 100selects an optical route from the port to which the Rest Info has notbeen assigned in Step S604. Here, for example, the optical route is aroute having the smallest cost value. On the other hand, in a case wherethe Rest Info has been assigned to the port as the route searchingsource (Yes in Step S603), the communication apparatus 100 determineswhether or not the F Bit is “1” in Step S605.

At this time, in a case where the F Bit is “0” (No in Step S605), thecommunication apparatus 100 selects an optimal route from among portshaving connectable IDs in Step S606. On the other hand, in a case wherethe F Bit is “1” (Yes in Step S605), the communication apparatus 100selects a port having a connectable ID as the next route in Step S607.Then, the communication apparatus 100 sets the selected port as theroute searching source in Step S608 and performs the process of StepS601 again.

On the other hand, in a case where the port is determined as a portlocated inside the communication apparatus including the end port (Yesin Step S602) in Step S602, the communication apparatus 100 acquires theRest Info of the route searching source in Step S609. In addition, thecommunication apparatus 100 further acquires the Rest Info of the endport in Step S610. Then, the communication apparatus 100 determineswhether or not the port as the route searching source and the end portcan be connected to each other in Step S611.

At this time, in a case where the port as the route searching source andthe end port can be connected to each other (Yes in Step S611), thecommunication apparatus 100 outputs the ports that have been selecteduntil then as a calculation result in Step S612. On the other hand, in acase where the port as the route searching source and the end port arenot connectable (No in Step S611), the communication apparatus 100performs the process of Step S613. In the process of Step S613, thecommunication apparatus 100 sets a port acquired by returning backwardby one hop as the route searching source and sets the port that has notbeen selected as the route not to be selected next time. In addition, inthe process of Step S613, in a case where a route is not selected at theport acquired by returning backward by one hop, the communicationapparatus 100 performs a process of returning the route searching sourcebackward by one hop and re-searching for a route and returns the routesearching source up to the port of the start node in a case where theroute is not selected. Then, the communication apparatus 100 determineswhether or not the search has been completed for all the routes in StepS614. At this time, in a case where the search has been completed forall the routes (Yes in Step S614), there is no selectable route for theroute from the start port to the end port that are designated, andaccordingly, the communication apparatus 100 outputs an error and endsthe process. On the other hand, in a case where the search has not beencompleted for all the routes (No in Step S614), the communicationapparatus 100 performs the process of Step S601.

Advantages of First Embodiment

As described above, even in a case where there is a restriction on theroute calculation, the communication apparatus 100 selects a route towhich the restriction is applied, and accordingly, compared to aconventional technique that causes an error without performing routecalculation to which the restriction is applied, a route relating todata transmission can be accurately selected. In addition, since thecommunication apparatus 100 autonomously performs the route calculationin a case where the start and end ports are designated, the operation ofthe GMPLS in a network including a plurality of communicationapparatuses can be performed without allowing a user such as amaintenance staff to recognize the restriction relating to the datatransmission. In addition, in the route calculation, the communicationapparatus 100 determines a route that is necessarily to be passedthrough and sets the route that is necessarily to be passed through tobe excluded from a target of the route calculation, whereby thecalculation amount can be decreased, and the processing load can bereduced.

[b] Second Embodiment

Until now, although an embodiment of the communication apparatus 100disclosed here has been described, an embodiment other than theabove-described embodiment may be employed. Thus, another embodimenthaving a “configuration” different from that of the above-describedembodiment will be described.

Configuration

The processing sequences, the control sequences, specific names, andinformation including various types of data or parameters (for example,information stored in the topology DB 108 or the like) presented in thedescription or the diagrams as above may be arbitrary changed unlessotherwise mentioned. For example, the information stored in the topologyDB 108 may differ in accordance with the type of the IF card or variousrestrictions in each communication apparatus.

In addition, the constituent elements of the communication apparatus 100illustrated in the diagrams are in a functional or conceptual sense andare not necessarily configured as illustrated in the diagrams in aphysical manner. In other words, a specific form of the separation orintegration of each apparatus is not limited to that illustrated in thediagrams, and the whole or a part of the apparatus may be functionallyor physically separated or integrated in arbitrary units in accordancewith various loads, the use status, or the like. For example, althoughthe non-volatile memory 111 has been described as an example of thenon-volatile memory illustrated in FIG. 1 or 2, it may be an example ofthe RAM illustrated in FIG. 1 or 2. In addition, the numbers or theconfigurations of the switch 101 and the IF 102 to the IF 104 are notlimited to those illustrated in the drawings.

According to an aspect of a communication apparatus and a method ofdetermining a route, which are disclosed here, there is an advantage ofaccurately selecting a route relating to data transmission even in acase where there is a connection restriction on a node included in anetwork.

All examples and conditional language recited herein are intended forpedagogical purposes to aid the reader in understanding the inventionand the concepts contributed by the inventor to furthering the art, andare to be construed as being without limitation to such specificallyrecited examples and conditions, nor does the organization of suchexamples in the specification relate to a showing of the superiority andinferiority of the invention. Although the embodiments of the presentinvention have been described in detail, it should be understood thatthe various changes, substitutions, and alterations could be made heretowithout departing from the spirit and scope of the invention.

What is claimed is:
 1. A communication apparatus comprising: a memorythat stores topology information shared by nodes included in a networkand representing connection states between the nodes and that storesfixed port information relating to a port, for which connectable portwithin the node is fixedly determined, the topology informationincluding port identification information used for identifying portsthat are connectable to each other within each node; and a processorthat determines a route by sequentially selecting a port that can beconnected to a port, to which transmission data is input, within eachnode, based on the port identification information and the fixed portinformation stored in the memory.
 2. The communication apparatusaccording to claim 1, wherein the processor acquires the portidentification information or the fixed port information that isassigned to each node in accordance with a type of interface card, andsets the port identification information or the fixed port informationin the memory.
 3. The communication apparatus according to claim 2,wherein, when a configuration of the ports is updated within any of thenodes, the processor sets the topology information in accordance withthe update.
 4. The communication apparatus according to claim 1,wherein, when a plurality of connectable ports are present, theprocessor determines the route, based on cost values that represent datatransmission states in routes, to a node as a linking destination.
 5. Anon-transitory computer-readable recording medium that stores therein acomputer program for determining a route, the computer program causing acomputer to execute: acquiring topology information shared by nodesincluded in a network and representing connection states between thenodes, the topology information including port identificationinformation for identifying ports that are connectable each other withineach node; acquiring fixed port information relating to a port, forwhich connectable port within the node is fixedly determined; anddetermining a route by sequentially selecting the port that can beconnected to a port, to which transmission data is input, within eachnode, based on the port identification information and the fixed portinformation.